Visual displays are virtually indispensable for rapid communication between a device capable of some level of data storage and access and/or processing and a user of such a device. For example, even prior to the introduction of personal computers, an alphanumeric display on a cathode ray tube or the like was used as an output of the data processor while keyboards and cursor controls were used as input devices. More recently, as the capabilities of display devices (e.g. color, resolution and various graphic attributes) have increased, display of graphic images has been found to be highly efficient to rapidly convey large amounts of information to a user.
It has also been found that a user can often directly interact with an image more efficiently than can be done through other types of input devices such as keyboards, particularly for manipulation of the image itself (e.g. zoom/size, panning, scrolling, rotation, etc.). At the present state of the art and with the development of highly miniaturized devices such as personal digital assistants (PDAs), so-called notebook, palm-top and tablet computers and, especially, wireless communication devices with substantial data processing capabilities such as so-called smart phones, display devices that are also able to sense touch, pressure or even proximity of a finger or other extremity of a user have supplanted many other types of input devices (e.g. light pens and various types of cursor controllers) for directly interacting with and selecting and manipulating images. For example, it is not uncommon for a user of a smart phone or tablet computer to use such a device to access and select from a large number of images such as a public or personal library or album of photographs and even use the cameras currently available in most smart phones to capture and store images into such a library or album or for a keyboard to be emulated with an image and touch sensors.
However, the display panels of such devices that may also be used as keyboards or to emulate other input structures are generally flat and most lack any provision for tactile feedback to which a user may have become accustomed and/or to allow a user to locate various available controls such as virtual buttons or knobs by touch rather than by sight. The process of locating a control that may exist only as displayed indicia distracts from concentration on a displayed image of interest and does not indicate that the display device has, in fact, recognized a user action as an input other than by a change in the display. These difficulties of use of touch panels are particularly acute for users having visual impairments. Therefore, various devices to provide a tactile or audible indication that a control command (e.g. actuation of a virtual key) has been recognized have been proposed and implemented with limited success.
More recently, it has been proposed to provide an overlay in the form of a controllable, possibly by microfluidics (which refers to both the study of the flow of fluids in space having a transverse dimension of micrometer size and devices that exploit such phenomena) transparent membrane over an otherwise featureless display screen to simulate knobs or keys that can be located and identified by touch. While such arrangements can provide tactile feedback and provide for allowing convenience using the touch screen interface, persons having visual impairments may still have substantial difficulty in comprehending, understanding and, especially, navigating images, in general, while some particular images and image features may present more difficulty than others for partially sighted persons. Further, while display of alphanumeric characters in braille on specially constructed “display” devices are known, no arrangements for allowing interaction with a graphic image by blind or severely visually impaired persons have been available. Even for persons with no significant visual impairment, an image of an object does not contain as much information about an object as the visible surface of the object itself and obscures depth information and other information that cannot readily be conveyed visually.